A sanctions bill in Congress has bipartisan support, but it could threaten delicate negotiations.

Will the Senate scuttle a nuclear deal with Iran?

The U.S. Senate could be about to scuttle a deal with Iran.In an unusual display of a lack of confidence in President Obama, a number of Senate Democrats have joined with Republicans to push a bill that could short-circuit the administration's efforts to negotiate with Iran over its nuclear program.Here's what you need to know about the stand off.The U.S. and Iran are in a kind of cold war.The Iranian hostage crisis did not help relations between the countries. (Getty …